Keys and doors!

From now on, wandering around the Blastaway arenas requires the player to collect keys and open doors with them - a little puzzle element that spices up the gameplay further ;)

CHANGELOG

• Added keys and doors.
• Touched up / adapted HUD graphics.
• Touched up tiles graphics.
• Added several arenas.
• Removed transparent walls.
• Updated/extended/improved manual.
• Made various internal improvements/bugfixes.