You can try to have just a regular, solid routine to get him down. Once he is in the crib, tell him you'll be right back. The first time, come back in five minutes. The second time, ten minutes, then fifteen, etc. until he is asleep. If you knows you are coming back, maybe that will help him feel more secure. Time is a tough concept when they are that young. You may have to do shorter increments of time.
If you are afraid he is going to get hurt falling out of the crib, you could take the rail off (if your crib converts) and put up a gate in the doorway instead. He may fall asleep on the floor, but at least he won't fall out of the bed.
These are tough times. By bedtime, I have little patience for my 3 year old's tricks. We are currently trying a reward system I learned from a middle school autism teacher to help him stay in bed and not cry. He's getting better, but not perfect. If it helps, every night you'll know there is at least one other parent struggling at bedtime, too.