#1 problem this game has : as you level up, less rooms are available to you so there's less variety and less people you can play with :( the level restrictions on rooms makes it seem like leveling up isn't worth it
Approval Rating: "It increases whenever a customer rates your Inn higher than your current Star Rating and decreases when they rate it lower." So apparently once you hit 5 star it's impossible to go above 0 approval rating, but it can and will go negative. Seems kind of contradictory since it's a 5-star Inn with a negative approval rating. Also, that +99 approval rating achievement is impossible to get later in the game.
The whole energy thing sucks in any game it's present in, but this game takes it to a whole new level. The way I see it, you have to actually spend your hard earned stat points on energy/stamina to even continue playing the game. Otherwise you can only perform a couple actions before having to wait for energy to replenish. Totally sucks balls.
Survival mode was a bit disappointing. I was expecting the game to continuously give me new opponents everytime I defeated the previous wave until eventually I quit/lose. It's less survival mode and more randomly generated stage.
There needs to be a survival mode of some kind (infinite mode). I hate building up all those towers, only to have the level finish and have to restart all over again on the next one.
Level 14 of the Alien campaign is really just not fair. Human rockets do an insane amount of damage (they can 1-hit you if you don't have shield) and I'm stick with a crappy weapon (Frozen Death SUCKS - sure it can shoot tons of rockets, but those things barely even scratch my enemy's HP) and both my teammates are just meatbags waiting to be blown up (occassionally doing so to themselves).
If anyone is having trouble on mission 9 : Inner Sanctum, it's actually very easy to beat. Each stage only has 3 hp, so what you do is send these units from bottom to top : Crusader, Hunter, and Knight. You have to do it very fast (use hotkeys) so they will reach the end before the enemy can get out their troops. Also, sending out the knight is a bit risky since it's slower, so use a couple of Crusaders as a substitute if you're not confident.