Using a game engine or not is a preference. It will depend on what exactly you are after. If you want to learn about the underlying concepts of rendering, collision detection, etc, then writing these yourself is perfectly acceptable, and a lot of fun. On the other hand, if you just want to get the game done without having to worry about the details then an engine is definitely the way to go.

Game engines range from very basic wrappers (which usually provides easier functions that take care of low level tasks) to highly complex abstractions in which the actual game development no longer resembles any specific platform - they also sometimes allow you to create the game once and deploy it to various platforms without any changes.

To implement a game based on that animation you might use the following:

• For each non-player character create a series of consecutive "frames" which when cycled gives the illusion of movement. These can be created in any graphics application (preferably in a texture map/atlas).
• For the player character, you will need an animated sequence for each "move", such as kick, punch, etc. Then play the correct sequence when the player triggers some action (ex. play the kick sequence when the player pushes a kick button).
• Each character should have a bounding box (i.e. a rectangle that defines the size and position of the character). The player character should probably have a different sized box based on the type of attack (i.e. the box for the kick action would extend farther to the right than the box for the punch action.
• Randomly spawn characters at the right of the screen and move them at some speed (based on type?) towards the player. During each iteration, test for collisions between the player and each non-player's bounding boxes. If a collision is found, check if the player is kicking or punching and kill the character that was hit, if the player is not attacking maybe damage him/her.

That is a very basic description of your problem and should give you enough ideas to research in order to implement a basic version :)

Some game engines you might want to look into:

• Andengine
• LibGDX
• Unity

If you are interested in learning about making android games specifically, have a look at this book:

• Beginning Android Games

There are many game engines out there that can help you can get the job done.

Here is a link for all the mobile game engines out there.

Android 2D Game Engines

Cocos2D-x

Language: C++

Orientation: 2D

Difficulty: Intermediate

Corona SDK

Language: Lua

Orientation: 2D/3D

Difficulty: Intermediate

EDGELIB

Language: C++

Orientation: 2D

Difficulty: Intermediate

GameMaker

Language: None (Graphical)

Orientation: 2D

Difficulty: Easy

GameSalad

Language: None (Graphical)

Orientation: 2D

Difficulty: Easy

HaxeFlixel

Language: Haxe

Orientation: 2D

Difficulty: Intermediate

libGDX

Language: Java

Orientation: 2D/3D

Difficulty: Intermediate

Marmalade

Language: C++

Orientation: 2D/3D

Difficulty: Intermediate

Stencyl

Language: ActionScript (optional), Objective-C (optional)

Orientation: 2D

Difficulty: Intermediate

Unity3D

Language: JavaScript (UnityScript actually), C# (Mono)

Orientation: 2D/3D

Difficulty: Intermediate

I answer in the order you asked

1. It is recommended to always use an engine, because they make the job easier, that's what they are for.

2. You can do certain animations and movements without a framework, but it actually becomes more complex with the code and logic.

3. Adobe Flash is useless on android. Most android devices do not run Flash without the user doing some things to get it.

4. The steps that I recommend are

   • research some engines
   • review some frameworks
   • select and engine depending on the logic of your game

5. Some engines are available for adventure games, puzzles, and other RPGs. Depending on your need go for one.

A few simple programs:

• App Game Kit
• Cocos2d for Android
• Corona SDK
• GameMaker
• Stencyl

You can start with these. Unity is the best engine, but the most complicated too.