The only mission I got stuck on was a convoy escort because I didn't know how to repair the bridge, I thought the game was bugged out until I read a loading screen tip later on explaining how to do it. It should probably be explained better in game.
I'd personally make grenades throw further since as of 0.7.0 they're exclusively a defensive tool but if that's how you intend them to be used then it's fine. I don't think this game needs leaning or any super advanced movement like some other people say, it's got a good balance of complexity and simplicity right now.
It's sort of unfortunate that the only way this game could exist is with AI, but I think it's really fun and fills a niche that isn't often explored so you won't see me complaining.