As a rule of thumb, don't make robots smaller than normal, players generally don't like it when they're harder to hit. This is the rule of thumb for robots that are about 40-50% smaller than normal. Your robots are so small they can barely be seen, they're faster than normal, and they build level 3 sentries. So I'd strongly recommend you remove them or make them normal sized.
As another rule of thumb, players generally don't like it when they need to
constantly check for Spies, especially in longer waves where the regular enemies trickle in a few at a time. Several of your waves have this problem, so I'd recommend you decrease the number of Spies that spawn and increase their respawn time.
The Loose Cannon Demomen rarely, if ever, fired their weapon. Instead they just kept charging it and hitting themselves with the explosive damage. Stick to normal primary weapons or melee weapons with Demomen, they do not know how to charge the Loose Cannon's shot or detonate stickies manually.
As for the map, there were multiple cases of robots being stuck inside spawn preventing the wave from being completed, make sure all spawnpoints are placed above ground and that there's nothing blocking them from moving out of spawn.
The large empty spaces in your map are boring to traverse and ultimately pointless, as there were no pickup items in the area and the robots never used these paths to reach the bomb hatch. Add some rooms or platforms - anything really to this area, and it would be a lot more interesting, you can also force robots to take certain paths using nav brush entities, giving the area some kind of purpose.
Lastly, your hatch area is very small and cramped, and the only spawn exit opens up right onto it. That means if there's a handful of Heavies standing around there when somebody respawns they're going to immediately die as they exit spawn. Spawns in MvM should have multiple exits, some distance from each other and the hatch, and shouldn't directly face the hatch so robots can't shoot in.
This map has some interesting ideas, like the sentry position which can defend the beginning and the end of the map at the same time, so I'd like to see you continue working on this. Remember that if you need testing, you can ask in our group's
Steam chat and somebody can upload your map to our MvM server.