Good game.
Looking down, I see no-one with a good, level-headed review that explains the criticism. So that's where I step in. First things first, yes, the controls are bad. Not "OMGWFT?!" bad, but they could definitely use work. The main issue is with jumping and climbing. I feel like a contortionist every time I try to jump for a ladder and grab it. I also often accidently press "up" instead of jumping. It would also be good to be able to turn around using the mouse, or to be able to move backwards while shooting, but those are minor.
The secrets in this game are good, as they are not perfectly hidden, and always give a clue, while sometimes still being devilishly twisted.
The weapon system is fairly balanced. Ammo for early weaponry becomes next to free, while the cutting edge costs a fortune to maintain, and the damage levels always balance out. One thing I would like to complain about is the DE, which deals 40 damage per gold, while the uzi (deals only slightly less dps) deals over 150 damage per gold spent. Some rebalancing in that regard might be useful.
All-in-all this game is fun to play, at least for a while. I have yet to complete it, but will probably come back to it.
If you think seven is a low score, know that I believe that 5/10 should be given to average games.