I've seen all of these in WAAAAAAAAAY too many maps so far (including my own ) and I and others are tired of constantly putting these in map assessments over and over again. I've listed the most common ones I could think of here. Before asking a question in the forums or having your map assessed, please save yourself some time and read through this list to make sure your map doesn't have any of these problems. 1. Leaks Leaks can create a huge number of problems in a map, anywhere from invisible water to weird, broken lighting. If you have an odd issue with your map, always start by checking the compile log. If you're fairly new to HL2 mapping, there's a nice compile log checker here where you can get a read-out on your log. If you do happen to have a leak in your map, but are having trouble getting rid of it, there's a very nice guide on fixing them here: http://developer.valvesoftware.com/wiki/Leaks I'm lazy and usually just do this after every compile to see if a pointfile (mapname.lin) was created (aka there was a leak) rather then reading through the compiling notes. 2. HL2 Sky By default, Hammer adds the same Half-Life 2 sky to every new map you create. Fixing this is rather easy, just go to Map > Map Properties and replace "sky_day01_01" with a TF2 sky. You can choose from this reference list here: https://developer.valvesoftware.com/wiki/Sky_list#team_fortress_2_materials.gcf 3. Little or no direction signs Running around in circles trying to find map objectives is not my idea of a fun time and not most other peoples either. This is one of the main reasons all the orange maps are so popular, new players (a good portion of the TF2 player base) can figure out their layout in a few seconds. I'm not saying over-simplify a map, but just having a few direction signs and markers in a map will drastically improve your maps adoption rate. The most common directions are prop_static's with the sign_gameplay worldmodel, though there are a few other prop_statics to choose from, as well as several good decals/overlays. Note: All the "signs_gameplay" models are set to "Battlements" by default, change the skin value and hit "apply" to see the other sign types. 4. Huge unavoidable open areas While this might work in other mods (and people like to have those great panoramas), huge open areas will give snipers an overwhelming advantage over the other classes. You can still have them, but if you do, also have at least one side route to bypass them so everyone doesn't have to play dodge the sniper bullet. Open areas should also have some form of cover at least every 1000~1500 units for players to hide behind and regroup and for spies to stop while recharging their cloak. 5. Repeating\Unvarying textures and terrain Large flat walls, floors, and displacements are nearly impossible to get to look nice, especially with only one, evenly lit, texture. There are a few ways to fix this, you aren't stuck only using different textures, you can add geometry and props to break up flat surfaces, and use different lighting strengths to create shadow contrasts as well. 6. Fullbright Lighting "But my map does have lighting!" If there are no shadows, no, no it doesn't. If there are no light entities anywhere in a map Hammer will give the map an ugly, fullbright lighting during the compile process by default (this can also happen if the map had a leak, see #1). Not only does fullbright lighting make your map look ugly and hard to discern between brush faces with the same texture, but it can also increase the file size of your map as well. If your not sure if your map is fullbright or not, load up your map in TF2, bring up the console screen, and type in "mat_fullbright 0", if a good portion of your map turns completely black, there is no lighting in it. A single light or light_spot entity is rarely enough for a whole map though, you have to space many, many light entities throughout your whole map to fully light it. The exception being if you have a mostly outdoor map, then a single light_env actually might be enough to light your map. Good lighitng will drastically improve the look of almost any map and is usually worth the time involved. Lighting tutorials: Advanced Lighting (Interlopers) 7. No cubemaps Weird purple/pink reflections are a dead giveaway for a map with either a lack of env_cubemaps, or a map with cubemaps that haven't been properly built. For reflections off of surfaces and models to work right, there needs to be a env_cubemap entity in the area. See here for more info: http://developer.valvesoftware.com/wiki/Cubemap. 8. Model textures on brushes Note: Hammer should filter out model textures by default, so you shouldn't have to worry about this. The texture browser contains model textures that go on models as well as regular textures meant for brush work. There's no one to blame but Valve for this and they are working on a fix, but until then, make sure the textures you're using do not have "model" in their name; ie "models/props_mining/wood_beam03". Model textures will not look right in-game when used on brushwork, a tell-tale sign of model textures on a brush is a flickering brush face that will change in contrast when viewed from different angles, becoming oddly dark or bright. 9. Improperly set-up spawn rooms If you are making a map for public servers, if players die in the spawn room upon changing classes, you have a problem. If all the players on a team spawn in the exact same location, you have a problem. If during a round players are repeatedly being killed by the other team before they've even left their spawn room, you have a problem. The problem is the respawn room in your map is not set-up properly, see here for a nice tutorial. 10. Little or no resupply items For non-arena maps, avoid forcing players to die or rely solely on medics and engineers to refill their ammo and health. Make sure you have a few item_healthkit's and item_ammopack's entities scattered around your map, especially near choke points and map objectives. Conversely, don't go overboard and place them all over the place, choose there locations carefully.