tutorial improvements

[nczempin]

just collecting some feedback; some of these require general gameplay changes and may deserve (or already have) their own issues

• The final wave is far too difficult.
• Teach the player that she cannot build on water
• React to events, such as "no more energy"
• Visualize more clearly when each resource is depleted (and teach how to get more of it)
• Make the waves with little to do shorter
• Explain that placing a laser tower at a corner makes it more effective
• Explain blocking

... more to come.

[nczempin]

#124
#125

[nczempin]

some good ideas to keep in mind:youtube.com/watch?v=BCPcn-Q5nKE