Level 41; shoot the wooden box and try to get underneath the safe fast enough. You can also try to shoot the safe across to where the spikes are and jump into the spikes.
With 29 lives remaining, use the weapon to shoot down the safe and try to get under it in time. On 45, push the lower safe underneath the one above you, then push the button. Push the safe again to get crushed by the safe on top of it.
7: Press K on your keyboard. 26: Get weapon and push the upper-left safe onto the 1st button. Then push the safe beside it onto the next switch. Jump up and fall down where the safe on the wooden box is. Shoot either the safe or the wooden box and try to get underneath the safe in time.
Level 28 is easy; grab weapon and shoot as fast as you can to hit the purple reflecting wall. Then step on the button and try to have the safe fall on top of you.
Level 3: Your mouse acts as a platform. XD Place your character underneath your mouse and use it to move him to the weapon. The rest is self-explanatory.
Level 32: 1) Put the explosive on the far right electric square with the safe to the right of it. 2) Activate the switch 3) Stand under the safe above you
Level 37: 1) Get weapon 2) Push the highest explosive box onto the left-most set of explosives 3) Shoot the explosive box on top, chain-reacting with the other ones 4) Stand under the safe above your head and wait
Level 26: 1) Get weapon 2) Push the highest safe (upper-left) down and onto the button 3) Push the safe beside it onto the switch 4) Jump up, fall down, and shoot the wooden box 5) Get under the safe in time.
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