Nyalamander is a mouse-controlled 2D scrolling shooter in the style of Salamander and the Gradius series, featuring six levels to beat and a handful of power-up items for the player to collect. Upgrades are in effect the second you pick them up, and when your ship is destroyed you can still save the options if you gather them before they disappear into space.

The level orientation switches from horizontal to vertical after each boss fight, and you have the option to continue playing from any stage you've beaten previously at the main menu screen. The autofire feature can be activated by scrolling up with the mouse wheel, and to turn it off you just need to scroll down using the same wheel.

Note that the game does not store a record of your unlocked levels between browsing sessions, and you'll have to start playing from stage one again if you close or switch browser windows. (source)