I played through the first 2 bosses last night and the UFO Boss I found too easy. All I had yo do was use my iron bow and iron armor to defeat it. I adds too 1-2 shots to kill(even the tanks) and the boss was taking 10damage a shot with the bow doing low single digits to me. I know its the first boss but in its current state it felt too easy. My suggestion is to increase the adds HP, especially on the tanks and increase the projectile speed on the mini-UFO adds. This would have caused me to take more damage then previously and not increase the difficulty too much. Other related note... The mech should be able to shoot ranged rockets if it is being hit and hasn't done damage to the character in 5 seconds. They should do low damage to the player but be able to break any block it hits with one blast. This might help with players cheesing it in a tunnel.