Constrictor!

The great big constrictor snake is circling Frog! Frog must fight to survive.

Controls:

Use W, A, S and D to move the frog around. Press space to scream. You can also use arrow keys in place of W/A/S/D. I prefer using arrow keys with my right hand and space bar with my left hand.

Backstory:

The constrictor's henchmen, the serpents, are tracking him down. But Frog has one trick up his sleeve: He can scream really loudly.

His screams can be deadly, but only if they hit the serpents right in the ear (headshot). While Frog fights the serpents, the constrictor is closing in, cutting off the space to roam. 

Serpents occasionally drop various powerups when they die. These powerups can be picked up by Frog to give extra features.

Powerups:

Active powerups can be seen on the right side of the screen, highlighted. Inactive powerups are faded.

Fireball:

The fireball powerup lasts for 10 seconds. Every scream/attack during this period is a fireball, which does not require hitting the serpents' heads to kill them. This can be combined with the arrow powerup, but when both are enabled, they take the appearance of the fireball.

Arrow:

The arrow powerup lasts for 10 seconds. Every scream/attack during this period takes the form of an arrow, unless fireball is also active. The arrow pierces through multiple serpents, not just one like a typical scream.

Expand:

The expand powerup activates instantly. It pushes the constrictor back one row in a huge explosion. It does not kill any serpents, and will only work if there is more than one circle created by the constrictor.

Rapidfire:

The rapidfire powerup lasts for 10 seconds. When active, a scream/attack has a negligible cooldown time, and a player can spam-click the space bar to attack rapidly.

Freeze:

The freeze powerup lasts for 10 seconds. It freezes the constrictor in place, and the constrictor does not advance while the powerup is active. 

Bomb:

The bomb powerup activates instantly. It explodes, killing all serpents on the screen. These serpents, as always, have a 50% chance of dropping a powerup.