Normal shot: Skull Shot: Skull Man's primary source of damage is his buster, being able to aim in 3 directions and having a fast travel speed makes it a good a trusty 2 DMG DPS. It can be comboed into Skull Bone for an extra 3 DMG.
Special 1: Skull Bone Toss: A 3 DMG bone which costs 4 EP that travels in an arc, you can aim how it gets tossed with the directionals but it's always aimed towards the opponent. A good strategy is using it at long ranges (for example at the start of a match) or up close since it can be harder than usual to hit it in mid range.
S2: Skull Cage: Skull Man can throw a secondary shield in a offensive way, dealing 2 DMG, costing 5 EP and having lower hitstun frames it can be really handy to get out of sticky ranged situations if it hits the opponent, while a opponent is caged in it he virtually cant use long ranges attacks or else they will get reflected right into his face, dealing damage to themselves but melee attacks dont get affected by it. Can be combo'd into Skull Bone.
Down S2: Skull Barrier: Skull Man signature move, his shield! One of the best ways to avoid damage might be with it since it costs 6 ep and has a catch, different of the other shields Skull Shield makes him completely invulnerable from any source of damage.
Extra: Resurrection: Skull Man passive ability is a EP costing resurrection, after reaching 0 HP he can come back to life in exchange of EP. It starts at 6 EP for 4 HP, after that every 4 EP adds one more 1 HP for a maximum of 22 EP for 10 HP.
Skull Man can stall an entire match for a long time with his arsenal so a lot of the time he will end up having the upperhand. If played right, combined with the best shield in the game you can be sure Skull Man will last a while.
He's really good against projectile based opponents so try to aim for reflects to maximize his damage output and even cancel the enemy setup. He's really good at sniping the enemy with his aimable ns so take advantage of that and try to choose stages where he can be far away.
He's great against projectile based opponents but the same can't be told to melee characters, they basically make his cage useless, out-speed him and even out-damage him, a truly scary thing for him.
As mentioned, he's bad at closed spaces and needs to be very careful against them or else he's going to get wrecked very easily