All upgrades add cash.
The princess is in trouble! Her castle is under attack from strange creatures and she needs a noble knight to save her...but it looks like we'll just have to settle with you. Draw your sword and loosen your arrows against the hordes of enemies that attack the castle. Collect coins to repair the castle or buy upgrades to help you in your quest.
W - Jump / Get on the horse
S - Get off the horse
A / D - Walk
E - Change weapon
Left Click - Attack