1) Proportional size of the bugs and coin gain. 

2) The life of the bugs decreases when hit with bullets. 

3) We can buy seeds and gain from selling.  

Some suggestions here:

1) The motivation to buy seeds and sell fruits is low in this game. 

Current play:

5 x 3 coins = 15 (a seed costs 20)
6 x 5 coins = 30 (a seed costs 40)
2 x 10 coins = 20 (a seed costs 80)

Suggested play:

5 x 30 coins = 150 (a seed costs 20)
6 x 50 coins = 300 (a seed costs 30)
4 x 100 coins = 400 (a seed costs 50)

The cost of the seeds should be pricier which is fine but players must be incentivised to plant pricier papaya seeds as the selling price to get the profit is better.  

2) Introduce time limit for each level so that player is motivated to plant more seeds to achieve level target if possible. 

3) Move the Harvest, Market and Shop buttons to the top of the screen horizontally rather than vertically. 

4) Introduce cost to water and shoot bullets at higher levels - this is akin to SG Govt give incentives to companies and citizens to start planting but in long run, companies and citizens need to manage their costs.

5) Show percentage to each plant when they will reach maturity. When watered, the percentage increase faster. Different speed for maturity of different seeds with the pricier seeds longer time to maturity .

6) Different backdrop for different level if possible. 

7) The size of the papaya should be bigger than tomato. 

That's all from me!"

Regards,
Mr Michael Sim